Gas turbine engines are typically employed to power aircraft. Typically a gas turbine engine will comprise an axial fan driven by an engine core. The engine core is generally made up of one or more turbines which drive respective compressors via coaxial shafts. The fan is usually driven off an additional lower pressure turbine in the engine core.
The fan includes a plurality of blades arranged around a hub. The blades may be made from metallic materials or composite materials.
Fan blades generally include a leading edge, a trailing edge, a pressure surface extending from the leading edge to the trailing edge and a suction surface extending from the leading edge to the trailing edge. A function of the leading edge is to split and guide air onto the pressure and suction surfaces of the blade. As such, the leading edge of the blade should have minimal surface roughness to minimise aerodynamic penalties.
During operation of a gas turbine engine, one or more of the fan blades may be impacted by foreign objects, including a bird strike. The leading edge of the blade should be strong enough to withstand such impacts, and also have a fracture toughness that limits the onset of damage to the blade after an impact.
It is further desirable that the leading edge can resist water and particle erosion, to maintain aerodynamic performance, reduce any rework needed, and prolong the life of the blade.
Conventionally, a leading edge member is manufactured as a separate component to the remainder of the blade. This separate leading edge member is then bonded, e.g. using adhesive, to the remainder of the blade.
One method of creating a leading edge member is described in U.S. 2013/004324, which uses electroplating to form the leading edge of the blade. To form the leading edge using electroplating, a tool is placed in a bath and electricity is passed through the tool. Ions from a solution in the bath form a coating on the tool. The tool is then removed from the bath and separated from the coating. This coating is then adhered to a leading edge of an aerofoil portion of a blade.